[1] Inst Oncol Angel H Roffo, Res Area, Buenos Aires, DF, Argentina
[2] Univ Sao Paulo, Inst Quim, Dept Bioquim, Sao Paulo, Brazil
[3] Univ Sao Paulo, Inst Matemat & Estat, Dept Ciencia Comp, Sao Paulo, Brazil
[4] Inst Oncol Angel H Roffo, Dept Surg, Buenos Aires, DF, Argentina
[5] Hosp Irmandade Snata Casa de Misericordia Sao Pau, Sao Paulo, Brazil